I collect based on aesthetics. I'll check the Chessex sets from time to time and just pick one up if I see something cool.
More importantly, I like to come up with a
color scheme of dice for my characters.
I'll get out up to three complete sets (and a few extra one offs d20s in case one keeps rolling low) and they'll be the ones I'll use for that character. Like, when I played a Dwarven Druid I got myself a set of stone grey dice and one that was grey and green set. When I play Arcane characters I bring out my purple dice. Sometimes I buy dice, sometimes I work with what I got.
I stil have my first polyhedral dice set! The numbers on my d20 don'T seem to be arranged in any sort of logical order, it's wild. Not even Magic Life Dice order!
My most special definitely has to be my translucent d20 that's damn near impossible to read, and actually only goes from 1-10. It's useless, deceptive, and I love it.
One of my friend had a D20 from a 'pound o dice' thing and we only realized after who knows how long that it had TWO 20 and no 1! Hilarious!